Gyrodactylus
| Gyrodactylus | ||||||||||||
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Gyrodactylus sp. |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Gyrodactylus | ||||||||||||
| Nordmann , 1832 |
Gyrodactylus is a flatworm genus from the class of hooked suction worms (Monogenea).
It is an ectoparasite (external parasite) and mainly affects the skin of fish, less often the gills. Here it lives parasitically on mucus and blood particles from the gills. A characteristic feature are its holding devices at the rear end made of a complex construction (opisthaptor) of various hooks, teeth and brackets. By means of these holding devices it is possible for him to anchor himself in the skin or the gills of his host. At the head end it has a mouth opening on the underside through which it takes in its food consisting of skin or blood particles. Like all flatworms , the Gyrodactylidaea have no anus opening.
In contrast to other gyrodactylids, Gyrodactylus is viviparous. This viviparity enables it to have a high reproductive rate. In a fertilized mother there is a developed larva that also already contains a larva. In this there is another one and in this one also grows a fourth. The larvae are therefore multiple redundant . If one larva is born, it can already deposit a second one and, after fertilization, form four new larvae again. The advantage of this reproduction is that the detour via free egg development and possible intermediate hosts or larval stages is avoided.
According to Khalil (1964), Gyrodactylus is not able to move freely in water, but can move like a leech on substrates in order to keep looking for ways to attach it. All skin worms and, above all, the gill worms show a high host specificity. In the case of gill worms, this often goes so far that they only parasitize on “their” host on a very specific gill arch, or only on the base or at the tips of the gill leaflets (Bauer 1991). Due to this specificity, outbreaks often only occur in a single species, so that other fish are not affected. If Gyrodactylus does not find a host, it is viable in the water for about ten days, depending on the water temperature and the general water quality.
Known species
treatment
An infestation with Gyrodactylus can be treated with the antihelminthic levamisole (e.g. Concurat®, Citarin®, Ripercol®) in the form of a bath solution or by feeding medicated live food. Levamisole has a direct cholinergic effect, in higher doses it also has an inhibitory effect on acetylcholinesterase and leads to spastic paralysis of the parasite. The active ingredient also has immune-stimulating properties in the host.
Note the deterioration in water quality when using glucose-containing preparations. Partial water changes must be carried out before and after treatment. Remnants of the medication are to be removed from the water by filtering through activated charcoal. Since the use of drugs has an oxygen-depleting effect, an additional administration of oxygen must be ensured during the treatment. Levamisole should not be used for open wounds because glucose-containing drugs cause massive bacterial bloom, which then infect open wounds and B. cause an infectious ascites .
swell
- Publication by Ludwig Katheriner
- Gyrodactylus v. Nrdm. From: Work from d. zool.-zoot. Inst. Würzburg, vol. X.-M. (3 plates) Wiesbaden, CW Kreidel, 1894; 2 sheets, 127 - 164 p. 8 Würzburg. Phil. Fac. Inaugural Diss. V. 1894
- Rudolf Hoffmann: Fish diseases . 2005, ISBN 978-3-8252-8241-7
